Alex Salmond's opponents have accused him of deceiving voters by making claims that Scotland is a "progressive beacon" for the rest of the UK, while covering up his failure to tackle poverty and inequality.

A senior Labour shadow cabinet member said Salmond had worsened the outlook for Scotland's most disadvantaged, despite asserting in his Hugo Young lecture in London on Tuesday evening that his government was fairer and more progressive than the UK government because it protects universal benefits.

Margaret Curran, the shadow Scottish secretary, said the first minister's government was pursuing policies which damaged the chances of the poorest students reaching university by cutting college budgets by 20%. She also accused it of failing to invest adequately in childcare and failing to redistribute resources to the most needy. Salmond's headline policies on free prescriptions, free university tuition for Scottish residents and freezing the council tax had only limited benefit for the neediest, she said, since they were not targeted and unnecessarily benefited the richest. Meanwhile, there were no details about how an independent Scotland would address these problems or foot the costs of these universal benefits.

"Alex Salmond wants to tell people what they can get for free but he doesn't tell people what the real costs are," Curran said. "The test for anyone truly progressive is not whether you get rich kids to university; it's whether you get everyone to university. That's the purest test of progressive politics."

Salmond will formally kickstart his drive to the independence referendum in 2014 on Wednesday by launching a public consultation on the staging and mechanics of the poll in the Scottish parliament before a speech at Edinburgh Castle, an event that drew Tory barbs that the first minister was acting "like a medieval king".

The first minister made his case that Scotland was now a model for social democratic politics in the British Isles a central part of his Hugo Young lecture, in honour of the former Guardian political commentator, arguing that Scottish voters are inherently more left of centre than those elsewhere in the UK. Salmond says that, even without control over Scotland's taxes and welfare system, his government is pursuing policies that are far more socially just than those of the coalition government in London. He also accused Ed Miliband and the Labour party of betraying their principles by siding with the coalition on its spending cuts.

Salmond acknowledged that many in England vigorously opposed the Iraq war and now oppose NHS privatisation, as they did in Scotland. He softened his expected attacks on Labour by saying Tony Blair's first government was elected "in the hope of progressive reform", but he insisted that "an independent Scotland can be a beacon for progressive opinion south of the border".

In his speech, he said the argument by former Labour leader John Smith that egalitarianism was a strong driving force in Scottish public life was "undoubtedly true". He added: "It is why policies which exacerbate inequality and remove basic safety nets are always likely to encounter fierce opposition in Scotland.

"And it is why anyone who accepted the union partly because of the compassionate values and inclusive vision of the postwar welfare state, may now be less keen on being part of a union whose government is in many respects eroding those values and destroying that vision."